Axillary Lymph Nodes and Breast Cancer

Lymph nodes of the armpits are central to the investigation

Mammography
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Lymph nodes are part of the immune system. The axilla, more commonly known as the armpit, contains lymph nodes that are involved in breast cancer.

Breast cancer can spread to axillary lymph nodes. The staging of breast cancer often involves axillary lymph node biopsy because this is usually the first site where breast cancer spreads. And many types of breast cancer treatment can lead to axillary lymphadenopathy, which is swelling of these nodes.

This article will outline the function of axillary lymph nodes and what happens when they are biopsied and dissected.

The Function of Axillary Nodes

The lymphatic system is comprised of lymph fluid, lymphatic vessels, and lymph nodes, as well as the spleen, tonsils, and adenoids. Lymph nodes are tiny organs that store white blood cells, called lymphocytes, that help fight infections and disease.

During a physical examination, healthcare providers will often examine the armpit to see if the axillary nodes are swollen. Around 75% of lymph fluid from the breasts drains into the axillary lymph nodes, making them important in the diagnosis of breast cancer.

If diagnostic tests (such as a mammogram) are indicative of possible breast cancer, axillary nodes may be surgically removed and examined to see if cancer is present. This is referred to as an axillary node biopsy. The biopsy can help your oncologist determine if cancer is present and begin the process of staging the disease.

Axillary Node Biopsy

A biopsy is a procedure in which sample tissue is removed to be tested by a pathologist in a lab. A common type of biopsy that's used in breast cancer staging is called a sentinel node biopsy. A sentinel node biopsy is usually performed on an outpatient basis in a hospital or specialized surgical center.

Sentinal node biopsy starts with injecting dye in the area. The first node that absorbs the dye is called the sentinel node. It is the first in the string of lymph nodes into which cancer cells are filtered. Because it is the first, it is more likely to deliver a more accurate result than a lymph node that is farther away.

That node is sent off to a lab to see if it contains cancer cells. If the sentinel node does not have cancer, it is unlikely that other nodes will have cancer and further surgery is not typically considered necessary.

Axillary Dissection

If cancer is present in a sentinel node, an axillary dissection will be performed to remove additional lymph nodes. The lymph node dissection will determine how many lymph nodes contain cancer cells. This information is important for treatment planning. And the removal of axillary lymph nodes that contain cancer cells can help prevent breast cancer from spreading to other areas of the body.

Axillary dissection is a relatively quick procedure that's done under general anesthesia. You will lie with your arm lifted over your head during the surgery.

For many women with breast cancer, this may be done at the same time as a lumpectomy or a mastectomy. During a typical axillary dissection, an average of two to 20 nodes are removed. The number of nodes affected is one of the key criteria for determining if the cancer is early (stages 1 to 2a) or advanced (stages 2b to 4).

Complications

Many women don't experience any problems due to axillary dissection, but the surgery may cause complications. Women are typically asked to avoid lifting heavy objects during recovery.

A common complication of this surgery is lymphedema. This is swelling of the arm, hand, breast, or torso due to the disruption of lymph vessels. Lymphedema can be painful, and it may go away (with treatment) within 24 months.

The approximate risk of lymphedema following axillary dissection is 14%. This can increase to 33% if radiation therapy is used.

Axillary dissection can also cause loss of sensation in the breast or axilla, limited arm mobility, and muscle weakness. Most of these symptoms are temporary and will improve over time.

Get prompt medical attention if you have any of the following symptoms:

  • High fever
  • Infection at the surgical site
  • Redness, painful swelling
  • Pus-like discharge

Summary

Axillary lymph nodes, located in the armpit, are part of the immune system. They help clear out disease-causing microorganisms. They can also be part of a breast cancer diagnosis. To learn if the breast cancer has spread from the breast, a breast cancer surgeon may remove axillary lymph nodes. A pathologist can determine if the cancer has spread by looking at the cells with a microscope.

A Word From Verywell

Axillary lymph node biopsy is often a standard procedure that's part of diagnosing breast cancer. Although removing lymph nodes can have unpleasant side effects, such as lymphedema, their removal may also prevent breast cancer from spreading to other areas of the body. If you are having any fever, swelling, or redness at the surgical site, call your doctor right away to have it examined.

Frequently Asked Questions

  • Where are lymph nodes in your armpit?

    They are located in the axilla, the pit of your arm. If they are swollen, you will be able to feel them with your hand. A doctor will be able to feel them during a physical examination.

  • Can breast cancer start in the lymph nodes?

    Breast cancer usually starts in the breast. When cancer breaks away from the original spot, it can spread through the lymph nodes. From there, cancer can spread through the lymphatic system to other areas of the body, which is one reason the lymph nodes are often removed if they contain cancer cells.

  • When should I worry about swollen axillary lymph nodes?

    Swollen axillary lymph nodes can be a sign of infection but can also be a sign of breast cancer. If they do not go away on their own within a few weeks, you should see a doctor. If you also have other symptoms, like a fever or night sweats, make an appointment right away.

  • Which lymph nodes does breast cancer spread to first?

    If breast cancer is metastatic, it spreads first to the axillary lymph nodes. It can also spread to the lymph nodes in the collar bone or near the breastbone.

4 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Vicente JS, Grande ML, Barquero CD, et al. Bilateral axillary and internal mammary drainage in breast cancer without prior surgery during sentinel node mapping. Indian J Nucl Med. 2011;26(4):205-7. doi:10.4103/0972-3919.106716

  2. Somner JE, Dixon JM, Thomas JS. Node retrieval in axillary lymph node dissections: recommendations for minimum numbers to be confident about node negative statusJ Clin Pathol. 2004;57(8):845–848. doi:10.1136/jcp.2003.015560

  3. Johns Hopkins Medicine. Breast Cancer: Lymphedema After Treatment.

  4. Johnson AR, Kimball S, Epstein S, et al. Lymphedema incidence after axillary lymph node dissection: quantifying the impact of radiation and the lymphatic microsurgical preventive healing approach. Ann Plast Surg. 2019;82(4S Suppl 3):S234-41. doi:10.1097/SAP.0000000000001864

Originally written by
Pam Stephan
Pam Stephan is a breast cancer survivor.
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